Conventional pop-up drain stopper assemblies include a push rod adjacent the faucet which when vertically translated actuates the stopper up or down. Connected to the push rod is a pivot rod, which protrudes into the drain conduit and engages a bottom portion of the drain stopper. Pushing the push rod down raises the drain stopper, thereby unsealing the drain stopper from the sink or basin and allowing water to drain. Pulling the push rod up causes the pivot rod to retract and pull the drain stopper with it so as to seal the sink or basin and retain water. A number of disadvantages attend such means. The traditional pop-up drain stopper assembly is cumbersome to adjust given varying sink dimensions. Further, the traditional pop-up drain stopper may require periodic adjustment in order for it to maintain a seal around the drain opening as the clip connecting the push rod to the pivot rod may slip over time.
Information relevant to attempts to address at least the first of these problems can be found in U.S. Pat. No. 4,594,738 (Gebert) wherein Gebert attempts to solve the problem of bathtub drains and overflows being at different heights on bathtubs of different dimensions. Gebert provides a drain and overflow device with a turn knob that, through a shaft, a lever, a cable, a pusher, two more levers, and another shaft, along with assorted connectors, causes the drain valve to open and close. However, Gebert suffers from at least one or more of the following disadvantages: the device is designed for bathtubs and would not easily adapt to sink drains; the device is mechanically complicated; and mechanical energy is lost in actuating the drain stopper.
Thus, in the applicant's experience there is a need for a pop-up drain stopper mechanism that is easily adjustable to sinks of various dimensions and that has an increased mechanical advantage to provide a consistently secure sealing of the drain opening. The device of the present invention is believed to accomplish all of the foregoing objectives.